Grinding samples using rotational and linear motion

An apparatus for generating a reciprocating motion for the purpose of grinding or homogenizing samples, the apparatus comprising:

• a connecting linkage that extends along a longitudinal axis;
• a holder, to hold a sample vial;
• a crank operatively connected at or near a first end of the connecting linkage, the crank configured to impart rotational motion to the first end of the connecting linkage, the crank having a diameter larger than a longitudinal length of a sample vial held by the holder;
• a sliding carriage operatively connected at or near a second end of the connecting linkage, the sliding carriage configured to restrict the second end of the connecting linkage to a linear path;
• and
• a motor operatively connected to the crank to rotate the crank,
• wherein the holder is configured to be secured to the connecting linkage at a variety of positions between the first end of the connecting linkage and the second end of the connecting linkage such that the holder, in use, moves with a combination of rotational and linear motion and the position of the holder on the connecting linkage changes the resulting pathway of the holder to be able to tailor the shape of the resulting pathway for grinding or homogenizing samples.